What the Bees Know About Pumpkin Pollination
By Autumn Prairie Pumpkins
There's a bee working the squash blossoms this morning. She has been at it since just after sunrise, moving from the wide open orange cups of the butternut vines to a patch of borage I tucked in at the edge of the beds last fall. She does not know it is World Bee Day. She is just doing her job, and without her, pumpkin pollination would not happen the way it needs to.
May 20 is World Bee Day, established by the United Nations in 2018 to recognize what bees do for us and what they are up against. This year's theme is "Bee Together for People and the Planet." It is a good day to slow down and notice the partnerships we do not usually see: the ones working quietly, without fanfare, keeping things alive.
Pumpkins and squash are among the most bee-dependent vegetables in the garden. Their flowers open for only a few hours each morning. A male blossom opens first. A female follows a day or two later, the small immature fruit visible just behind her petals. A bee visits both, carrying pollen on her body. A few days after a successful visit, the fruit behind that female flower begins to swell. That is the whole story, and it is remarkable every time.
The Partnership at the Heart of Every Harvest
There is a bee called the squash bee (Peponapis pruinosa) that evolved specifically alongside cucurbit plants in North America. It nests in the ground near squash and pumpkin plantings, emerges early in the morning to match the short window when pumpkin blossoms are open, and does almost nothing else. It is one of the clearest examples in nature of two living things shaping each other over thousands of years. The bee needs the flower. The flower needs the bee. The rest follows.
Squash bees are not always present in every garden, especially where soil has been heavily worked or treated. Honeybees, bumblebees, and other native pollinators fill in the gap when they are around. But they stay around for a reason. A garden that has something blooming from early spring through late fall is a place bees come back to. A garden that offers only pumpkin blossoms for two weeks in July is not quite enough to hold them.
The vine borer resistant varieties we grow here, the Seminole Pumpkin and Waltham Butternut among them, tend to bloom generously over a long season. The flowers are large and open. The nectar is plentiful. These were not bred for a shipping container. They were selected by people who were paying attention to the whole plant, and part of what makes them work in a real garden is that they hold up their end of the partnership.
What You Can Do in Your Garden This Week
If you are planting pumpkins now or will be soon, a few small additions make a real difference in how well pollination goes once the flowers arrive.
Plant something for the bees near the patch. A pot of herbs going to flower, borage self-seeded from last year, a row of phacelia tucked at the edge. Borage is worth singling out: it blooms continuously, the bees love it with an intensity that is almost funny to watch, and it self-seeds politely in most gardens without becoming a problem. Plant it once and it tends to come back on its own.
Avoid spraying anything on or near open pumpkin flowers. Even garden-safe products applied early in the morning, when bees are most active and flowers are at their widest, can reduce pollination. If pest pressure requires treatment, do it in the evening, after the blossoms have closed for the day.
If you notice female flowers that do not set fruit, where the small pumpkin behind the blossom shrivels instead of growing, you may have a pollination gap. Hand pollination is a straightforward fix. Our guide to hand pollinating pumpkins walks through the whole process. But the deeper answer is always more bees, more often, and a garden that gives them reason to stay. The companion planting guide for pumpkins in Kansas goes further on building that kind of garden from the ground up.
Small Things, Long Reach
The United Nations estimates that roughly a third of the food humans eat depends on pollination. Pumpkins are on that list. Coffee is on that list too. Two things we think about quite a bit on this particular Kansas patch.
There is something worth sitting with in that. The morning cup of coffee and the seed going into the ground in May both exist because of a much older system, one that runs on nectar and pollen and a bee finding her way from one flower to the next. We do not run that system. We can support it or we can make it harder. That choice gets made mostly in small decisions: what to plant near the patch, when to spray and when not to, whether to till or to leave the ground undisturbed for a bee that might be nesting there.
Bees do not need a day named for them to keep working. But noticing what they do, really noticing the whole web they are part of, changes how you garden. It slows things down in a good way. You start thinking about next year's bees alongside this year's harvest. The two are not separate things.
Pumpkin pollination does not happen by accident in a healthy garden. It happens because something you planted brought a bee close enough to do the work. That is not a small thing. That is the whole thing.
From the patch in Newton, Kansas.